Electric toothbrushes generally comprise a handle which contains inter alia a power supply and a drive motor, and a head which includes one or more brush part bearing oral hygiene parts to be driven by the motor, generally in rotary motion about a rotation axis transverse to the head—handle direction, and connected by a transmission means to the motor. The term “oral hygiene part” as used herein refers to a part which contributes to oral hygiene, for example by cleaning the teeth, gums or other oral tissues, and/or polishing the teeth, and/or massaging the gums or other oral tissues. Often there is a neck between the handle and the head, and containing such a transmission means e.g. a drive shaft. Often the head is replaceable, typically being either replaceably connectable to the end of the neck remote from the handle, or being integral with the neck and the neck being replaceably connectable to the handle at its end remote from the head.
Often the rotary motion is oscillatory, i.e. motion involving reciprocal angular displacement about a mean position. Sometimes the rotary motion also involves a reciprocal back and forth movement of the brush part along the rotational axis direction.
Numerous constructions of electric toothbrush are known, for example the applicant's own Dr BEST “E-FLEX” (™) electric toothbrush launched in 2000 which has a brush part mounted for oscillatory rotary motion. U.S. Pat. No. 6,000,083 discloses an electric toothbrush having both rotating and static i.e. non rotating brush parts.
It is known from EP-A-0 990 424 (Procter & Gamble) to provide an electric toothbrush having a motor-driven first brush part and a second brush part which is static, i.e. integrally made with the head and immovable relative to the head. It is also known from EP-A-1 132 057 (Unilever) to provide an electric toothbrush having bristle-bearing segments linked flexibly to the head by means of a leaf hinge of a plastic material integral with the head.
Very often the oral hygiene parts comprise plural bristles arranged in discrete tufts or mats on a surface of the brush part. Typically such bristles are made of a nylon polymer e.g. the well known Tynex™. Often bristles are the only oral hygiene parts of a toothbrush. Toothbrushes having elastomeric oral hygiene parts on their head to contact the teeth and gums are known.
Numerous types of elastomeric oral hygiene parts are known. GB-A-2 040 161 discloses longitudinally extending elastomer strips. GB-A-2 214 420 and WO-A-00/49911 both disclose a toothbrush having a head from which project small rubber pyramids. GB-A-214 701 discloses a toothbrush having oral hygiene parts comprised of strips of crepe rubber, in one theoretically discussed embodiment of which the strips may have bristles sandwiched between the strips of crepe rubber. EP-A-0 360 766 discloses small rubber cylinders with knobbed ends. U.S. Pat. No. A-4,128,910 discloses a toothbrush having rubber oral hygiene parts of various pyramid and ridge shapes. U.S. Pat. No. A-4,277,862 discloses a toothbrush having resilient gum massage parts along the outer edges of the bristle pattern. U.S. Pat. No. A-4,288,883 discloses rubber cones. U.S. Pat. No. 5,040,260 discloses a toothbrush having a head from which extend small rubber cones. WO-A-96/15696 discloses a toothbrush head provided with strips of a flexible and resilient material, typically a non-elastomeric nylon material, and typically aligned either perpendicular to or parallel to the longitudinal direction. WO-A-96/28994 discloses elastomer bars extending perpendicular to the longitudinal direction and parallel to the edges of the head in combination with bristle “bars” having an elongate cross section cut across the bristle direction, and also discloses a curved rubber “scooping bar” at the tip end of the head. WO-A-97/16995 discloses elastomer “bristles”. WO-A-98/18364 discloses tooth polishing pads or finger-like structures. WO-A-99/37181 discloses an outer ring of rubber fingers surrounding an inner dense pack of bristles. WO-A-00/64307 discloses rubber bars with a generally triangular cross section. WO-A-00/76369 discloses elastomeric massaging parts with rotational symmetry through an angle of 120° or less e.g. cylinders. WO-A-01/21036 discloses a longitudinally extending elastomeric wall-like member running for at least half the length of the head.
Electric toothbrushes having elastomeric oral hygiene parts are known, e.g. WO-A-01/01817 discloses an electric toothbrush having a head with elastomeric fingers or arcuate lamellae mounted on it. EP-A-0 435 329 discloses an electric toothbrush having interdental points in rubber mounted on it.